Radiotherapy involves the production of a beam of high-energy ionising radiation, usually x-rays or a beam of electrons or other sub-atomic particles. This is directed towards a target region of the patient, and adversely affects the target cells (typically tumour cells) causing an alleviation of the patient's symptoms.
In order to ensure that the radiation is delivered to the patient safely, radiotherapy treatment is necessarily a complex process involving many steps. As part of that process, a number of different personnel may have cause to use the machine for different reasons, but not all will generally need access to the same machine parameters. For example, a radiotherapy technician may need to control the system directly to deliver a particular plan of treatment, whereas a nurse may need only to access the system to position a patient on the patient support. Similarly, a repair and maintenance technician may need to access parameters which are generally not available to others. It would therefore be useful to gain a measure of control over who can issue commands to the radiotherapy system, and ensure that each command has been issued by a person of appropriate qualifications.
It would also be advantageous to design a medical environment with minimal exposed keys and protruding surfaces. Various fluids may be involved in the treatment process, which could get caught on levers and pulleys, or may be spilt accidentally. A system which can withstand such accidents will in general be able to maintain an operative state for a longer period of time.